I believe the issue here is that you've updated to the latest versions of our Toolset plugins which don't allow HTML to be added to as options for you checkbox fields.
Unfortunately i'm unable to tell which version would've contained this. However my advise is to always ensure that you're running the latest versions of our plugin as to maintain compatibility with wordpress core as well as the later php versions.
If you have a backup of your site where this worked then you can go ahead and restore this version. I've checked on the changelogs but there isn't any specific information on this one.